US3723352A - Supported silver catalysts - Google Patents

Supported silver catalysts Download PDF

Info

Publication number
US3723352A
US3723352A US00109640A US3723352DA US3723352A US 3723352 A US3723352 A US 3723352A US 00109640 A US00109640 A US 00109640A US 3723352D A US3723352D A US 3723352DA US 3723352 A US3723352 A US 3723352A
Authority
US
United States
Prior art keywords
silver
gold
catalyst
aluminodisilicate
calcium sodium
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00109640A
Inventor
W Alexander
Evoy J Mc
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Air Products and Chemicals Inc
Original Assignee
Air Products and Chemicals Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Air Products and Chemicals Inc filed Critical Air Products and Chemicals Inc
Priority to US10964071A priority Critical
Application granted granted Critical
Publication of US3723352A publication Critical patent/US3723352A/en
Anticipated expiration legal-status Critical
Application status is Expired - Lifetime legal-status Critical

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00Catalysts comprising molecular sieves
    • B01J29/04Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/70Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65
    • B01J29/72Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65 containing iron group metals, noble metals or copper
    • B01J29/74Noble metals
    • B01J29/7407A-type
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D301/00Preparation of oxiranes
    • C07D301/02Synthesis of the oxirane ring
    • C07D301/03Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
    • C07D301/04Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen
    • C07D301/08Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase
    • C07D301/10Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase with catalysts containing silver or gold

Abstract

A SOLUTION OF THERMALLY DECOMPOSABLE SALT OF SILVER AND A GOLD SALT SOLUTION ARE IMPREGNATED INTO A FOAMED CALCIUM SODIUM ALUMINODISILICATE SUPPORT AND CALCINED TO PROVIDE A SUPPORTED SILVER CATALYST CONTAINING A TRACE AMOUNT OF GOLD, SAID CATALYST HAVING EFFECTIVENESS IN THE SYNTHESIS OF ETHYLENE OXIDE.

Description

United States Patent 3,723,352 SUPPORTED SILVER CATALYSTS Warner Alexander, Brookhaven, and James E. McEvoy,

Springfield, Pa., assignors to Air Products and Chemicals, Inc, Philadelphia, Pa. No Drawing. Filed Jan. 25, 1971, Ser. No. 109,640 Int. Cl. B013 11/40 US. Cl. 252-454 3 Claims ABSTRACT OF THE DISCLOSURE A solution of thermally decomposable salt of Silver and a gold salt solution are impregnated into a foamed calcium sodium aluminodisilicate support and calcined to provide a supported silver catalyst containing a trace amount of gold, said catalyst having effectiveness in the synthesis of ethylene oxide.

BACKGROUND OF THE INVENTION Field of invention This invention relates to catalysts having a crystalline aluminosilicate support and Group I-B components as the active components, the aluminosilicate containing calcium and sodium compounds.

Prior art SUMMARY OF THE INVENTION In accordance with the present invention, a foamed calcium sodium aluminodisilicate prepared by the thermal recrystallization of a calcium sodium Zeolite A is employed as the support for silver in a catalyst for the oxidation of ethylene to ethylene oxide. The silver is deposited by impregnation of a solution of a thermally decomposable salt of silver into the foamed calcium sodium aluminodisilicate, followed by drying and thermal decomposition of the anion of the silver salt.

DESCRIPTION OF EMBODIMENTS The invention is further clarified by reference to a plurality of examples.

Examples 1-11 Meta kaolin powder is refluxed with aqueous sodium hydroxide in accordance with Kumins et al. 2,544,695, and the recovered dry powder is compressed into zeolite pellets consisting essentially of sodium alu- 3,723,352 Patented Mar. 27, 1973 mino disilicate. These pellets are ion-exchanged with a solution of calcium chloride to provide calcium sodium alumino disilicate pellets. Measurable amounts of sodium remain in the product because of the conventional incompleteness of routine procedures for ion exchange of crystalline zeolites. Synthetic zeolites are generally identified by the cation occupying most of the ion exchange sites without referring to less abundant cations. As mol percent of ion exchange capacity, the pellets are about 51-90% Ca and about 10-49% Na O, desirably at least Ca. Said pellets of calcium sodium alumino disilicate are heated during about 30 minutes to about 1100 C. and maintained at about 1100 C. for about 10 minutes to provide ceramic foam particles. Each foamed particle has a volume of approximately four times the volume of the initial calcium sodium alumino disilicate pellet. The foamed calcium sodium alumino disilicate pellets contain the same ratio of Ca to Na ions as the pellets before heating. The foamed pellets have a bulk density of from about 8 to 19 lbs./ft. or about 0.13 g./cc. to about 0.3 g./cc. The surface area is approximately 2 mP/g. The pore size distribution shows about 67% of the pore volume consists of pores so large that they are measured in microns instead of in angstroms. Most of the pores are of a size in the 7 to 30 micron range. The pore volume is about 5 cc./g., or about 10 times that of some alumina carriers. When the foam pellet is heated for 24 hours at about 1090 C., the shrinkage is only 0.3% and when the same 24 hours test is evaluated at a still higher tem perature of 1260" C., the shrinkage is of the magnitude of 0.6%. The crushing strength of the pellets is about 10 lbs. The particles have a specific heat of about 0.224 B.t.u./ lb.

An oxidation catalyst was prepared from the foamed pellets. The pellets were impregnated with a small amount of gold chloride and dried. Then a concentrated solution of silver nitrate was impregnated into the pellets. The molar ratio of deposited silver to gold was about 51 to 1.

The impregnated catalyst was treated with an aqueous solution of sodium hydroxide, thereby converting the silver nitrate to a hydrated silver oxide. The pellets were washed with water to remove conveniently removable sodium hydroxide and nitrate ion. Some of the silver and gold may have been removed by the water-washing. The pellets were dried at C. and had an ignition loss at 500 F. of 12.1%. The sodium oxide content of the pellets was 2.3%, the silver content was 33.7% and the gold content was 1.2%. Thus the silver to gold mol ratio was 51 to l. The catalyst was heated in a stream of hydrogen at about 300 C. to volatilize the residual nitrate and moisture content of the catalyst and to assure the formation of high surface area metallic silver and gold. Thethus reduced catalyst was treated with nitrogen to flush out sorbed hydrogen and then with dry air at about 300 C. to provide high surface area silver oxide on the ceramic foam support. The density of the thus impregnated catalyst was higher than the density of the ceramic foam by reason of such silver oxide.

TABLE I.-TEST RESULTS FOR ETHYLENE OXIDE CATALYST The catalyst was employed in a reactor utilizing about 4 cc. of the catalyst (1.3 g.). The once-through reactant stream contained 5% ethylene, 9% oxygen, 86% nitrogen, and 0.2 part per million of ethylenedichloride. Each change of process conditions was deemed the starting of a different example. The effiuent gases were analyzed by chromatographic techniques. No recycle stream was utilized. The results of the evaluation are summarized in Table I.

It is noted that the previously described catalyst consists of a major amount of crystalline calcium sodium aluminodisilicate foam matrix, and a minor amount (e.g. 33.7%) silver, and a trace amount (e.g. 1.2%) of gold, so that the silver to gold atom ratio is about 50 (e.g. 51.5).

Example 12 A supply of catalyst support pellets was prepared by converting pellets of calcium Zeolite A to ceramic foam particles by heating at about 1050 C. for about minutes following the procedure of Example 1. A series of oxidation catalysts is prepared by impregnating silver nitrate into the ceramic foam pellet, impregnating an amount of gold which is about 2 mol percent the amount of silver to maintain a Ag/Au atom ratio of about 50, and heating the impregnated pellet in a stream of H at about 300 C. to decompose the nitrate ion and thus provide a catalyst consisting of a minor amount of silver and a trace amount of gold in a matrix of calcium sodium aluminodisilicate foam. Concentration ranges from about 1% to about silver activated by gold for maintaining the Ag/ Au ratio of about have utility as supported silver catalysts.

By a series of tests it is established that the foamed matrix particle, prior to incorporation of the catalytic metal component, must consist essentially, of non-zeolitic synthetic calcium sodium aluminodisilicate, the proportions being 5090% C210 and 10-50 Na O per mole of alumina in the aluminodisilicate, said calcium sodium aluminodisilicate having a bulk density of less than 0.3 kilogram per liter and having structural strength and rigidity, said calcium sodium aluminodisilicate comprising a plurality of uniformly distributed interconnected open pores contributing a porosity of at least 75 volume percent, the pores having diameters from about 5 to about 30 microns contributing about 75% of the porosity, said calcium sodium aluminodisilicate having a surface area of less than about 5 square meters per gram, and an initial fusion temperature of at least 1250 C.

The foamed calcium sodium aluminodisilicate was pulverized and the powder subjected to standard X-ray diffraction procedures to provide the following data:

TABLE A d, A.: I/l 8.63 12 4.98 19 4.31 16 4.19 33 4.04 23 3.85 51 3.76 16 3.63 14 3.36 14 3.26 65 3.19 100 3.13 16 3.04 19 3.00 70 2.88 30 2.57 19 2.51 14 2.30 26 2.14 14 2.09 21 2.08 19 Such X-ray data suggest either a mixture possibly comprising nepheline, plageoclase, and anothite, or possibly a unique single crystalline species having no name other than foamed calcium sodium aluminodisilicate.

What is claimed is: 1. The method of preparing a supported silver catalyst, which method includes the steps of:

preparing Zeolite A type of sodium aluminodisilicate subjecting said sodium aluminodisilicate to ion exchange with a solution of a calcium salt to prepare calcium sodium aluminodisilicate, said calcium so dium aluminodisilicate being of granular particle size and corresponding to the composition converting granular particles of said calcium sodium aluminodisilicate to porous granular particles of foamed crystalline calcium sodium aluminodisilicate by heating at a temperature within the range of 850 C. to 1200 C. for a time of at least 10 minutes;

impregnating the foamed granular particles with a liquid solution of a gold salt and with a liquid solution of a silver salt having a thermally decomposable anion, the amount of silver impregnated into the particles being in the range of about 1 to about 40% by weight and the gold being in an amount such that the atomic ratio of silver to gold is about 50:1;

heating the impregnated particles in a glass stream at conditions decomposing the thermally decomposable anion to bond the gold and the silver to the particle, thereby providing a trace amount of gold and said amount of siliver distributed throughout the foamed crystalline calcium sodium aluminodisilicate support; and cooling the granular particles.

and cooling the granular particles.

2. A supported silver catalyst comprising silver in an amount of about 1 to about 40% by weight and an amount of gold such that the atomic ratio of silver to gold in the catalyst is about 50 to 1 distributed throughout a low density non-zeolitic crystalline synthetic calcium sodium aluminodisilicate foam, the proportions being 50- CaO and 1050% Na O per mole of alumina in the aluminodisilicate, said calcium sodium aluminodisilicate foam support having a bulk density of less than about 0.3 kilogram per liter and having structural strength and rigidity, said calcium sodium aluminodisilicate foam comprising a plurality of uniformly distributed interconnected open pores contributing a porosity of at least 75 volume percent, the pores having diameters from about 5 to about 30 microns contributing about 75 of the porosity, said calcium sodium aluminodisilicate foam having a surface of less than about 5 square meters per grams, and an initial fusion temperature of at least 1250 C.

3. The catalyst of claim 2 in which the presence of the calcium sodium aluminodisilicate foam is evidenced by an X-ray diffraction essentially corresponding to Table A.

References Cited UNITED STATES PATENTS 3,396,112 8/1968 Burrows 252382 X 3,440,181 4/1969 Olstowski 252-62 3,497,455 2/1970 Ahr 252-62 3,585,217 6/1971 Titzenthaler 260348.5 3,594,310 7/1971 Pollitzer 252455 Z CARL F. DEES, Primary Examiner US. Cl. X.R.

US00109640A 1971-01-25 1971-01-25 Supported silver catalysts Expired - Lifetime US3723352A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US10964071A true 1971-01-25 1971-01-25

Publications (1)

Publication Number Publication Date
US3723352A true US3723352A (en) 1973-03-27

Family

ID=22328771

Family Applications (1)

Application Number Title Priority Date Filing Date
US00109640A Expired - Lifetime US3723352A (en) 1971-01-25 1971-01-25 Supported silver catalysts

Country Status (1)

Country Link
US (1) US3723352A (en)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3905917A (en) * 1973-06-15 1975-09-16 Matsushita Electric Ind Co Ltd Catalyst for purifying exhaust gas
EP0709360A1 (en) * 1994-10-28 1996-05-01 AGENCY OF INDUSTRIAL SCIENCE & TECHNOLOGY MINISTRY OF INTERNATIONAL TRADE & INDUSTRY Method for production of alcohol, ketone, and alderhyde by oxidation of hydrocarbon
US5525741A (en) * 1993-08-06 1996-06-11 Sumitomo Chemical Company, Limited Process for producing olefin oxides
US20060282046A1 (en) * 2005-04-13 2006-12-14 Horn Jeffrey L Device and method for subcutaneous delivery of blood clotting agent
US20070031515A1 (en) * 2005-04-04 2007-02-08 Stucky Galen D Inorganic materials for hemostatic modulation and therapeutic wound healing
US20070065491A1 (en) * 2005-02-09 2007-03-22 Z-Medica Corporation Devices and methods for the delivery of blood clotting materials to bleeding wounds
US20070276308A1 (en) * 2006-05-26 2007-11-29 Huey Raymond J Hemostatic agents and devices for the delivery thereof
US20070275073A1 (en) * 2006-05-26 2007-11-29 Z-Medica Corporation Clay-based hemostatic agents and devices for the delivery thereof
US20090162406A1 (en) * 2007-09-05 2009-06-25 Z-Medica Corporation Wound healing with zeolite-based hemostatic devices
US7595429B2 (en) 2003-09-12 2009-09-29 Z-Medica Corporation Calcium zeolite hemostatic agent
US7604819B2 (en) 2006-05-26 2009-10-20 Z-Medica Corporation Clay-based hemostatic agents and devices for the delivery thereof
US20090299253A1 (en) * 2003-09-12 2009-12-03 Hursey Francis X Blood clotting compositions and wound dressings
US20100228174A1 (en) * 2006-05-26 2010-09-09 Huey Raymond J Clay-based hemostatic agents and devices for the delivery thereof
US8858969B2 (en) 2010-09-22 2014-10-14 Z-Medica, Llc Hemostatic compositions, devices, and methods
US8938898B2 (en) 2006-04-27 2015-01-27 Z-Medica, Llc Devices for the identification of medical products
US9072806B2 (en) 2012-06-22 2015-07-07 Z-Medica, Llc Hemostatic devices
US9326995B2 (en) 2005-04-04 2016-05-03 The Regents Of The University Of California Oxides for wound healing and body repair
US9821084B2 (en) 2005-02-15 2017-11-21 Virginia Commonwealth University Hemostasis of wound having high pressure blood flow using kaolin and bentonite

Cited By (43)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3905917A (en) * 1973-06-15 1975-09-16 Matsushita Electric Ind Co Ltd Catalyst for purifying exhaust gas
US5525741A (en) * 1993-08-06 1996-06-11 Sumitomo Chemical Company, Limited Process for producing olefin oxides
EP0709360A1 (en) * 1994-10-28 1996-05-01 AGENCY OF INDUSTRIAL SCIENCE & TECHNOLOGY MINISTRY OF INTERNATIONAL TRADE & INDUSTRY Method for production of alcohol, ketone, and alderhyde by oxidation of hydrocarbon
US5623090A (en) * 1994-10-28 1997-04-22 Agency Of Industrial Science & Technology, Ministry Of International Trade & Industry Method for production of alcohol, ketone, and epoxide by oxidation of hydrocarbon
US8252344B2 (en) 2003-09-12 2012-08-28 Z-Medica Corporation Partially hydrated hemostatic agent
US20090299253A1 (en) * 2003-09-12 2009-12-03 Hursey Francis X Blood clotting compositions and wound dressings
US7595429B2 (en) 2003-09-12 2009-09-29 Z-Medica Corporation Calcium zeolite hemostatic agent
US8557278B2 (en) 2005-02-09 2013-10-15 Z-Medica, Llc Devices and methods for the delivery of blood clotting materials to bleeding wounds
US20070134293A1 (en) * 2005-02-09 2007-06-14 Huey Raymond J Devices and methods for the delivery of blood clotting materials to bleeding wounds
US8512743B2 (en) 2005-02-09 2013-08-20 Z-Medica, Llc Devices and methods for the delivery of molecular sieve materials for the formation of blood clots
US8257731B2 (en) 2005-02-09 2012-09-04 Z-Medica Corporation Devices and methods for the delivery of molecular sieve materials for the formation of blood clots
US20070065491A1 (en) * 2005-02-09 2007-03-22 Z-Medica Corporation Devices and methods for the delivery of blood clotting materials to bleeding wounds
US20100121244A1 (en) * 2005-02-09 2010-05-13 Z-Medica Corporation Devices and methods for the delivery of molecular sieve materials for the formation of blood clots
US9821084B2 (en) 2005-02-15 2017-11-21 Virginia Commonwealth University Hemostasis of wound having high pressure blood flow using kaolin and bentonite
US20070031515A1 (en) * 2005-04-04 2007-02-08 Stucky Galen D Inorganic materials for hemostatic modulation and therapeutic wound healing
US7858123B2 (en) * 2005-04-04 2010-12-28 The Regents Of The University Of California Inorganic materials for hemostatic modulation and therapeutic wound healing
US9326995B2 (en) 2005-04-04 2016-05-03 The Regents Of The University Of California Oxides for wound healing and body repair
US20060282046A1 (en) * 2005-04-13 2006-12-14 Horn Jeffrey L Device and method for subcutaneous delivery of blood clotting agent
US8938898B2 (en) 2006-04-27 2015-01-27 Z-Medica, Llc Devices for the identification of medical products
US20100228174A1 (en) * 2006-05-26 2010-09-09 Huey Raymond J Clay-based hemostatic agents and devices for the delivery thereof
US8202532B2 (en) 2006-05-26 2012-06-19 Z-Medica Corporation Clay-based hemostatic agents and devices for the delivery thereof
US7604819B2 (en) 2006-05-26 2009-10-20 Z-Medica Corporation Clay-based hemostatic agents and devices for the delivery thereof
US9867898B2 (en) 2006-05-26 2018-01-16 Z-Medica, Llc Clay-based hemostatic agents
US8257732B2 (en) 2006-05-26 2012-09-04 Z-Medica Corporation Clay-based hemostatic agents and devices for the delivery thereof
US8343537B2 (en) 2006-05-26 2013-01-01 Z-Medica, Llc Clay-based hemostatic agents and devices for the delivery thereof
US8383148B2 (en) 2006-05-26 2013-02-26 Z-Medica, Llc Clay-based hemostatic agents and devices for the delivery thereof
US8460699B2 (en) 2006-05-26 2013-06-11 Z-Medica, Llc Clay-based hemostatic agents and devices for the delivery thereof
US20070275073A1 (en) * 2006-05-26 2007-11-29 Z-Medica Corporation Clay-based hemostatic agents and devices for the delivery thereof
US20070276308A1 (en) * 2006-05-26 2007-11-29 Huey Raymond J Hemostatic agents and devices for the delivery thereof
US8784876B2 (en) 2006-05-26 2014-07-22 Z-Medica, Llc Clay-based hemostatic agents and devices for the delivery thereof
US8846076B2 (en) 2006-05-26 2014-09-30 Z-Medica, Llc Hemostatic sponge
US8114433B2 (en) 2006-05-26 2012-02-14 Z-Medica Corporation Clay-based hemostatic agents and devices for the delivery thereof
US7968114B2 (en) 2006-05-26 2011-06-28 Z-Medica Corporation Clay-based hemostatic agents and devices for the delivery thereof
US9333117B2 (en) 2006-05-26 2016-05-10 Z-Medica, Llc Clay-based hemostatic agents and devices for the delivery thereof
US9078782B2 (en) 2006-05-26 2015-07-14 Z-Medica, Llc Hemostatic fibers and strands
US20100233248A1 (en) * 2006-05-26 2010-09-16 Z-Medica Corporation Clay-based hemostatic agents and devices for the delivery thereof
US10086106B2 (en) 2006-05-26 2018-10-02 Z-Medica, Llc Clay-based hemostatic agents
US20090162406A1 (en) * 2007-09-05 2009-06-25 Z-Medica Corporation Wound healing with zeolite-based hemostatic devices
US8858969B2 (en) 2010-09-22 2014-10-14 Z-Medica, Llc Hemostatic compositions, devices, and methods
US9889154B2 (en) 2010-09-22 2018-02-13 Z-Medica, Llc Hemostatic compositions, devices, and methods
US9352066B2 (en) 2012-06-22 2016-05-31 Z-Medica, Llc Hemostatic devices
US9603964B2 (en) 2012-06-22 2017-03-28 Z-Medica, Llc Hemostatic devices
US9072806B2 (en) 2012-06-22 2015-07-07 Z-Medica, Llc Hemostatic devices

Similar Documents

Publication Publication Date Title
US3769202A (en) Catalytic conversion of hydrocarbons
US3374182A (en) Caustic-treated zeolites
US3140252A (en) Hydrocarbon conversion with crystalline acid-metal aluminosilicates
US3384667A (en) Production of primary and secondary amines
US3702886A (en) Crystalline zeolite zsm-5 and method of preparing the same
US3433589A (en) Method of preparing faujasite-type crystalline zeolites
Kerr Chemistry of crystalline aluminosilicates: VII. Thermal decomposition products of ammonium zeolite Y
US3692470A (en) Crystalline zeolite zsm-10
US3314752A (en) Synthetic zeolite
US3140251A (en) Process for cracking hydrocarbons with a crystalline zeolite
US3459676A (en) Synthetic zeolite and method for preparing the same
US3247195A (en) Synthetic zeolite and method for preparing the same
US3493519A (en) Hydrothermally stable catalysts of high activity and methods for their preparation
US3173854A (en) Catalytic hydrocracking with a crystalline zeolite containing hydrogenation metals and a rare earth
USRE29948E (en) Crystalline silicates and catalytic conversion of organic compounds therewith
US4248739A (en) Stabilized pillared interlayered clays
EP0167755B1 (en) Improved zeolite l
EP0002079B1 (en) Crystalline silicates and method for preparing same
US3827968A (en) Aromatization process
EP0011900B1 (en) Process for the conversion of dimethyl ether
US3008803A (en) Crystalline zeolite b
US4427789A (en) Activation of zeolites
US4046859A (en) Crystalline zeolite and method of preparing same
AU626593B2 (en) Removal of mercury from fluids by contact with activated zeolite a
US3114603A (en) Process for synthetic zeolite a